Wendy Heiger-Bernays, PhD
Department of Environmental Health, BU School of Public Health
Boston University Superfund Research Program http://www.busrp.org/

Winter, 2014

Derivation of TCE Toxicity Values and Implications for Risk Management

On October 29, 2014, Dr. Wendy Heiger-Bernays of Boston University’s Superfund Research Program gave a seminar entitled, Derivation of TCE Toxicity Values and Implications for Risk Management, to the Kentucky Energy and Environmental Cabinet, Department of Environmental Protection (KYDEP). The seminar, which was part of the University of Kentucky Superfund Research Center’s (UK-SRC’s) monthly seminar series for state agency regulatory staff, focused on the U.S. Environmental Protection Agency’s (EPA’s) 2011 Integrated Risk Information System (IRIS) Final Assessment for trichloroethylene (TCE). The seminar also highlighted relevant TCE exposure scenarios for vapor intrusion sites. In addition to the formal seminar, Dr. Heiger-Bernays and Dr. Kelly Pennell (of the University of Kentucky Superfund Research Center) met with state agency staff and discussed various strategies for addressing TCE in indoor air at vapor intrusion sites. Dr. Pennell had previously presented vapor intrusion seminars to KYDEP (February 2014 and March 2010). Following those seminars, KYDEP specifically asked for more information on TCE toxicity values, to which Dr. Heiger-Bernays’ seminar responded.

TCE is a common contaminant in groundwater in the United States and countries where this degreasing agent was and is used. In addition to exposures that occur through contact with contaminated water, vapor intrusion results in inhalation of TCE in residential and commercial buildings. EPA IRIS provides an oral cancer slope factor and inhalation unit risk value, but the non-cancer effects are of particular interest because toxicological studies have shown developmental effects at very low doses for short durations in susceptible populations (i.e. near or below chronic levels). As a result, the non-cancer risk assessment is currently the determinant in the management of many TCE-contaminated environments. Regulatory agencies across the country are challenged with addressing these short-term exposure risks, while continuing to protect against chronic exposures. To date, few states have established final guidance about how to manage TCE inhalation acute exposure risks. Management scenarios range from ventilation to home evacuation.

As a member of the Massachusetts Department of Environmental Protection Waste Site Clean-Up Advisory Committee, Dr. Heiger-Bernays discussed with KYDEP approaches being used by Massachusetts and other states for managing inhalation exposure risks of TCE at vapor intrusion sites. Several days following the seminar, state officials from KYDEP, Dr. Heiger-Bernays and Dr. Pennell continued to correspond via email about specific vapor intrusion sites in Kentucky for which the seminar information was relevant.

During Dr. Heiger-Bernays’ visit to Kentucky, she also met with several researchers within UK-SRC and toured the research core facility. Throughout her visit, several areas of overlapping research interests emerged and opportunities for continued collaboration are being pursed.

Seminar was be held October 29, 2014 in Frankfort Kentucky at the KYDEP, noon.